IX HORNS AS A SEXUAL CHARACTER 201 
same os cornu, which may however be branched, but which is in 
the same way covered by a layer of modified integument; this is 
known as the “velvet”; it only lasts for a certain period, and is 
then torn off by the exertions of the animal itself, leaving behind 
the bony core, which is popularly termed the horn. It will be clear 
that here is only a difference of comparative unimportance; the 
same essential features are present in both groups of animals, but 
the modification of the epidermis has progressed along different 
lines. Both can be referred back to the primitive conditions seen 
in the paired horns of the Giraffe. Even the difference, such as it 
is, is bridged over by the Antelope Antzlocapra, where the os cornu 
is bifid and the horn is periodically shed, as is the velvet of the 
stag; but in the stag the bony part of the horn is also shed, a 
state of affairs which has no parallel in the Hollow-horned 
Ruminants. The great Sivatherium may conceivably be an 
annectant form between the two types of compound horns, 7.e. 
those of the Antelope and those of the Deer. This creature had 
two pairs of horns, of which, naturally, only the bony cores remain ; 
the hinder pair of these were branched. But although so far they 
resemble the Deer’s horns rather than the Antelope’s, Dr. Murie 
has thought that they were covered by a horny sheath and not by 
soft skin as in the Deer. In any case these horns were apparently 
never shed, which is a point of likeness with the Antelope and of 
difference from the Deer. Apart therefore from the nature of the 
covering of the bony cores, there are good grounds for looking’ 
upon them as intermediate between those of the Deer and those 
of the Antelopes. 
The horns of the Ruminants are frequently a secondary sexual 
character ; this is especially the case with the Deer. The Rein- 
deer is, however, an exception, both the stags and the does 
having horns. That they are associated with the reproductive 
function is shown by their being shed after the period of rut, 
the destruction of the velvet at that period, and also by the effect 
upon the horns which any injury to the reproductive glands 
produces. Some useful facts upon this latter head have been 
amassed by Dr. G. H. Fowler,’ who noticed in a series of stags, 
horns showing various degrees of degeneration in the antlers pro- 
duced by varying degrees and periods of gelding. From the facts 
1 
““ Notes on some Specimens of Antlers of the Fallow Deer, etc.,” Proc. Zool. Soc. 
1894, p. 485. 
